Improvement of intelligent corrosivity-detection and corrosion-protection for reinforcing steel

Highlights: • The intelligence of corrosivity-detection and corrosion-protection by Mg can be improved through proper Al alloying. • A Mg-based alloy with a high Al content is ideal for the intelligent corrosivity-detection and smart corrosion-prevention. • The intelligent Mg-Al corrosivity-detector and smart corrosion-protector must have a chloride-sensitive breakdown potential. • Although Al or an Al-based alloy is too active in a strong alkaline solution, Al alloying can enhance Mg passivity. A series of Mg-Al alloys were fabricated by means of magnetron-sputtering, aiming to improve the intelligence of Mg as a smart concrete corrosivity-detector and corrosion-protector. The effect of Al alloying on Mg dissolution in a simulated concrete pore solution (SCPS) without and with Cl⁻ contamination was systematically investigated. The results showed that proper Al alloying could significantly enhance the intelligence of Mg in corrosivity-detection and corrosion-protection by reducing the self-dissolution, avoiding the over-protection, sensitively probing increased corrosivity, and effectively protect the steel activated by chlorides.